The present invention relates to an additive for an electrolyte solution including a lithium salt having an oxalato complex as an anion and a phosphate compound, a non-aqueous electrolyte solution including the additive and a lithium secondary battery including the electrolyte solution. More particularly, the present invention relates to an additive for an electrolyte solution for forming a lithium secondary battery having an improved lifetime characteristic and good power characteristics.
As the technical development and the demand on mobile devices increase, the demand on secondary battery as an energy source has been rapidly increased. Among the secondary batteries, a lithium secondary battery having a high energy density and voltage has been commercialized and widely used.
Recently, the lithium secondary battery has been developed as a power source of an electric power storing equipment or a power source for mounting on a vehicle in a medium-large size industry as well as a power source for a small-sized device.
Particularly, a battery for hybrid electric vehicles is required to have high power characteristics for operating an auxiliary motor of an engine power instantaneously or high power characteristics at a low temperature under a severe condition.
In order to use the battery for the power source in the medium-large size industry, a battery having a long lifetime may be necessary when considering that a plurality of the batteries may be assembled to use, and the exchange of the batteries may incur expenses.